SACRAMENTO – According to the 2017 March of Dimes Premature Birth Report Card, California’s preterm birth rate increased to 8.6 percent reaching a six-year high.

California, with the highest number of births and one of the most diverse populations in the country, earned a “B” grade on the Report Card.

Premature birth (before 37 completed weeks of pregnancy) is the largest contributor to the death of babies in the U.S.

“This year’s report card is a real setback,” said Peyton Mason-Marti, MPH, March of Dimes Regional Director of Maternal Child Health. “California had been making steady progress toward our 8.1% goal, reducing the preterm birth rate from 9.1 percent in 2007 to 8.3 percent in 2014. The subsequent two years of increases to 8.6 percent in 2016, takes us back to where we were in 2010.”

The March of Dimes Report Card highlights the large gaps in the preterm rate between races and regions within California.

The preterm birth rate among black women in California is 46 percent higher than the rate among all other women.

While race is not the cause of preterm birth, a woman’s race and where she lives can place her at higher risk. Santa Clara, Ventura and Orange counties earned an “A” grade for their preterm birth rates.

Among the 100 cities in the U.S. with the greatest number of births (latest data is for 2015), Irvine, California had the lowest rate of preterm birth in the country at 5.8 percent. Yet one in 10 babies is born preterm in the Central Valley counties of Fresno and Kern.

“The 2017 March of Dimes Report Card demonstrates that moms and babies in this country face a higher risk of preterm birth based on race and zip code,” said Stacey D. Stewart, president of the March of Dimes. ”We see that preterm birth rates worsened in 43 states plus the District of Columbia and Puerto Rico, and among all racial/ethnic groups. This is an unacceptable trend that requires immediate attention. The March of Dimes is dedicated to giving every baby a fair chance for a healthy start in life, and our work is more vital than ever.”

The nation’s rate of preterm birth increased again in 2016, after nearly a decade of declines, earning the nation a grade of “C.” More than 380,000 babies are born preterm in the U.S. each year, facing a greater likelihood of death before their first birthday.

An additional 8,000 babies were born prematurely in 2016 due to the increase in the preterm birth rate between 2015 and 2016, March of Dimes says.

Babies who survive an early birth often face serious and lifelong health problems, including breathing problems, jaundice, vision loss, cerebral palsy and intellectual delays.

In addition to the human toll, preterm birth accounts for more than $26 billion annually in avoidable medical and societal costs, according to the National Academy of Medicine.

“In addition to discovering new ways to prevent premature birth, and improve the care that women receive, it’s essential that we improve the broader social context for health,” said Paul E. Jarris, MD, MBA, chief medical officer of the March of Dimes. “Only then will our nation be able to level the playing field for mothers and babies in every community.”